🚀 go-pugleaf

In article <19960911.131014.09@clares.demon.co.uk>
          DClare@clares.demon.co.uk (Dave Clare) wrote:

> In message <19960910.180911.68@axis.demon.co.uk> Nick Craig-Wood wrote:
> 
> > You are wrong I'm afraid.  You can get internal or external TAs just like
> > modems.  Most external TAs will work with an Acorn machine and most of them
> > emulate AT commands to appear like a modem.
> > 
> > I've used my TA with !TCPIP, Freenet, Arcterm7, Connector & the Ant Suite.
> > 
> > If you want to use X25 ie HDLC framing then most TAs define a simple
> > conversion to and from async.  You then connect your TA to your computer at
> > anything up to 460.8 kbits/s and away you go.  If you meant X25 over the D
> > channel then you can't do this yet over BTs network and I am betting that if
> > it ever becomes available it will be prohibitively expensive.
> 
> Can you or someone post a clear and concise article on what we need
> (hardware and software), what it costs, how fast it works etc. 
> 
> I know nothing about ISDN but if you have a system working on the RPC then
> PLEASE tell us all about it.

I will try a short summary.

The only possibility to get ISDN on an Acorn is an external ISDN terminal
adaptor (short form TA). These are a kind of "ISDN modems", because they
work just as standard analogue modems (with the common Hayes AT command set),
even if they are not real modems in the sense of "modulator-demodulator".

Today there are various TAs available with very different features and
prices. The following hardware is all euro ISDN compatible (used in Germany
and I think in the UK, too), prices are in DM because I am too lazy ;-)
All TAs I will mention include the channel bundling feature.

1. ZyXEL Elite 2864DI
   This is a combined ISDN TA and a V.34 modem with many additional features
   like offline fax receive (computer is offline, modem spools fax data into
   its own RAM for later or direct printout on a PCL printer or "download"
   via computer), voice capability and a fast parallel interface (no Acorn
   drivers currently available). Also includes one a/b-adaptor (allows usage
   of old analogue device). The serial port goes up to 460.800 bps. It is
   possible to use V42bis over ISDN connections.
   The analogue modem part is V.34 capable and also able to use the former
   proprietory ZyXEL 16k8/19k2 modes.
   Price around 1100 DM.
2. ZyXEL Omni TA 128
   This is a "pure" ISDN TA. All standard features, 2 a/b adaptors, V42bis
   possible. Two serial ports (up to 460.800 bps).
   Price 550 DM.
3. EEH Datalink ELink 310
   Again a "pure" ISDN TA. Only the most basic features, no V42bis, no a/b
   adaptors, DTE up to (IIRC) 115.200 bps.
   Price was 700 DM, but the product should be superseeded by now.
4. EEH Datalink ELink 343
   A combined ISDN TA/V.34 modem. All standard features, no special goodies.
   Price unkown, but not cheap. There is also an older model named ELink 324
   which incorperated a V.32bis modem instead of a V.34 one.

Note: there is a new ISDN modem in preparation by EEH Datalink as an answer
      to the new ZyXEL TA and to superseed the old ones.

5. Elsa MicroLink ISDN/TL V.34
   A combined ISDN TA/V.34 modem. Standard ISDN features including V42bis.
   The analogue modem has voice capability (Rockwell standard).
6. Telelink SAFEline TWIN
   A combined ISDN TA/V.34 modem, includes V.34+ "standard". No special
   features known.
   Price around 1100 DM.
7. Telelink SAFEline ISDN-TA
   Pure ISDN TA.
   Price around 800 DM.

There is also a USR combi modem in preparation, to date only the internal
PC version is available.

Note: all hardware is available in Germany for the given price. No guarantee
if it works in the UK or is available.

Summary: all ISDN modems support channel bundling, so the maximum throughput
is 128 kbit/s (64 kbit/s per channel). Via V42bis data compression it is
possible (in theory) to get 4 times the throughput. This of course only
can work with uncompressed data.

If you want to use channel bundling an probably V42bis, the standard Acorn
serial port is too slow, so you probably should buy one of the extra serial
podules (despite their vast overpricing).

Software - just the same as with a standard modem.

So long, Steffen

-- 
Steffen Huber           LambdaComm System - Welcome to Trollinger Country
hubersn@lcs.wn.bawue.de                       acorn2@ftp.uni-stuttgart.de
... Is there intelligent life on planet earth? Yes, but I'm only visiting.